What is the incidence rate of oxalic acid poisoning in a specific location?

Oxalic Acid Poisoning Incidence

Oxalic acid poisoning is extremely rare in most developed countries but has emerged as a significant public health problem in specific regions, particularly rural Sri Lanka, where it represents an emerging epidemic of intentional self-poisoning. 1

Geographic and Epidemiologic Context

Endemic Regions

• In Southern Sri Lanka, oxalic acid poisoning has become a popular method of self-harm among youth, with a prospective observational study documenting 115 cases over a defined study period, representing an "emerging epidemic." 1
• The epidemic in Sri Lanka is driven by locally produced household laundry detergents containing oxalic acid (12.5 g per sachet) combined with potassium permanganate, which are readily available and unregulated. 1
• The case fatality ratio for oxalic acid ingestion alone is 25.4% (95% CI 14-39%), with the majority of deaths occurring within one hour of ingestion. 1

Developed Countries

• In Western countries, direct oxalic acid poisoning is exceptionally rare, with most oxalate-related toxicity occurring indirectly through ethylene glycol poisoning rather than direct oxalic acid ingestion. 2, 3
• The medical literature contains predominantly case reports rather than epidemiologic studies, indicating the rarity of this poisoning in developed nations. 2, 3, 4

Clinical Significance and Mortality

Acute Toxicity Profile

• Ingestion of more than one sachet (>12.5 g) is associated with a 13-fold increased risk of death (risk ratio = 13.26,95% CI 3.2-54). 1
• When both potassium permanganate and oxalic acid are ingested together, the case fatality ratio is 9.8% (95% CI 3.2-21%). 1

Pathophysiology of Poisoning

• Direct oxalic acid ingestion causes severe metabolic acidosis, acute renal failure requiring dialysis, and gastrointestinal mucosal ulceration. 2, 3, 1
• Elevated plasma oxalic acid levels are associated with reduced total and ultrafilterable calcium levels due to calcium oxalate deposition in soft tissues. 4
• Renal biopsy in poisoned patients reveals acute tubulointerstitial nephritis with diffuse acute tubular damage and refractile crystals in tubules. 2

Contrast with Chronic Oxalate Disorders

Primary Hyperoxaluria

• Primary hyperoxaluria (PH) is an autosomal recessive disorder that is genuinely rare, with PH type 1 being the most prevalent subtype but still affecting a small population globally. 5
• More than 70% of PH patients develop kidney failure due to chronic calcium oxalate deposition, but this represents endogenous overproduction rather than acute poisoning. 5

Key Clinical Pitfalls

• Do not assume oxalic acid poisoning is rare everywhere—in regions where oxalic acid-containing products are readily available and unregulated, it represents a significant poisoning epidemic. 1
• Do not delay hemodialysis in suspected cases, as patients benefit symptomatically from early dialysis despite the rapid progression to death in severe cases. 2, 3, 1
• The rapid time course to death (within one hour in many cases) makes medical management extremely challenging, emphasizing the importance of prevention through product regulation. 1